1. Field of the Invention
The present invention relates to a scroll compressor, and more particularly, to a scroll compressor having a frame fixing structure capable of easily and firmly fixing a frame to a hermetic container, and a frame fixing method of the scroll compressor.
2. Description of the Conventional Art
Generally, a compressor is a device for converting mechanical energy into compression energy of a compression fluid. The compressor is divided into a reciprocating compressor, a scroll compressor, a centrifugal compressor, and a vane compressor.
The scroll compressor sucks, compresses, and discharges gas by using a rotation body like the centrifugal compressor and the vane compressor differently from the reciprocating compressor using a linear motion of a piston.
FIG. 1 is a longitudinal section view showing a scroll compressor in accordance with the conventional art, and FIG. 2 is an enlargement section view of ‘A’ part of FIG. 1.
As shown, an upper frame 2 is fixed to an inner upper portion of a hermetic container 1 having an accommodation space therein, and a lower frame 3 is fixed to an inner lower portion of the hermetic container 1.
A motor 6 composed of a stator 4 and a rotor 5 rotatably coupled to an inner side of the stator 4 is installed between the upper frame 2 and the lower frame 3. A balance weight for controlling an unbalanced rotation of the rotor 5 is mounted at upper and lower portions of the rotor 5.
A rotation shaft 7 rotated together with the rotor 5 is forcibly pressed into an axial hole 5a formed at a center of the rotor 5 in a vertical direction. An upper end portion of the rotation shaft 7 coupled to the rotor 5 is rotatably inserted into a supporting hole 2a of the upper frame 2, and a lower end portion of the rotation shaft 7 is rotatably inserted into a supporting hole 3a of the lower frame 3.
A compression unit 10 composed of a fixed scroll 8 fixed to the upper frame 2 and an orbiting scroll 9 rotatably coupled between the fixed scroll 8 and the upper frame 2 is installed at an upper side of the upper frame 2. An eccentric portion 7a formed at the upper end portion of the rotation shaft 7 to be eccentric is inserted into a coupling hole 11a of a boss portion 11 formed at a lower end portion of the orbiting scroll 9.
An oil feeder 13 for sucking oil 12 contained in a lower portion of the hermetic container 1 and supplying the oil to a frictional part of the compression unit 10 through an oil passage 7b formed at the rotation shaft 7 is coupled to a lower end portion of the rotation shaft 7.
A suction pipe 14 for sucking refrigerant gas and a discharge pipe 15 for discharging compressed refrigerant gas are installed at a lateral surface of the hermetic container 1 with a height difference. Also, a pressure separating plate 16 for separating a low pressure portion 20 where refrigerant gas sucked into the hermetic container 1 through the suction pipe 14 exists from a high pressure portion 21 where the refrigerant gas sucked into the hermetic container 1 is compressed in the compression unit 10 and stays before being discharged through the discharge pipe 15 is fixed to an upper portion of the fixed scroll 8.
A check valve 19 for preventing refrigerant gas discharged through a discharge hole 8a formed at the fixed scroll 8 from backward flowing is coupled to an upper surface of the fixed scroll 8.
An unexplained reference numeral 8b denotes a wrap of the fixed scroll, 8c denotes a refrigerant suction hole, 9a denotes a wrap of the orbiting scroll, 16a denotes a discharge hole, 30 denotes a rotation preventing member, and P denotes a compression pocket.
In the scroll compressor, when power is supplied to the scroll compressor, the rotor 5 of the motor 6 is rotated and thereby the rotation shaft 7 is rotated. According to this, the orbiting scroll 9 coupled to the upper end portion of the rotation shaft 7 is rotated.
The orbiting scroll 9 is orbited by having an eccentric distance from a center of the rotation shaft 7 to a center of the eccentric portion 7a as a radius, and the orbiting scroll 9 is prevented from being rotated by the rotation preventing member 30.
When the orbiting scroll 9 is orbited, the wrap 9a is orbited by being engaged with the wrap 8b of the fixed scroll 8. At this time, refrigerant gas is introduced into the lower pressure portion 20 of the hermetic container 1 through the suction pipe 14. Then, the refrigerant gas is introduced into the compression pocket P formed between the wrap 8b of the fixed scroll 8 and the wrap 9a of the orbiting scroll 9 through the refrigerant suction hole 8c formed at the fixed scroll 8. As the orbiting scroll 9 is continuously orbited, a volume of the compression pocket P is decreased and the refrigerant gas is compressed. At this time, the compressed gas moves towards a center portion of the compression pocket P, and is discharged out through the discharge hole 8a of the fixed scroll 8.
While the compression operation is performed, oil 12 contained in the inner lower portion of the hermetic container 1 is sucked by the oil feeder 13 together rotated with the rotation shaft 7. The sucked oil 12 is supplied to the compression unit 10 through the oil passage 7b. 
As shown in FIG. 2, under a state that a welding pin 21 is inserted into a pin inserting groove 2b formed at a lateral surface of the upper frame 2, the welding pin 21 is welded to the hermetic container 1 by a welding portion W penetrating a through hole 1a of the hermetic container 1.
However, in the conventional scroll compressor, since the upper frame 2 is not directly fixed to the hermetic container 1 but is fixed to the hermetic container 1 by the welding pin 21, a welded portion of the upper frame is weak. According to this, the welded portion between the upper frame and the hermetic container is easily detached from each other due to vibration generated when the compressor is driven.